T. LOUIS - A platter of cheese in hand, Karen Hughes rushed to the back of the campaign plane yesterday on a mission for her boss, Governor George W. Bush.
''Cheese, anyone? Cheese?'' she offered, laughing loudly. To a newcomer baffled to see the senior aide playing flight attendant, Hughes explained: ''It's a metaphor for the bizarre nature of the story today.''
The story was about rats - the word superimposed onto a frame of a negative television ad about Vice President Al Gore. But the visit by Hughes, and her overtures to a wary press corps, were noteworthy themselves, suggesting the campaign is trying to counter some harsh vibes it has begun to give off.
Until recently, Bush was the undisputed ''nice-guy'' candidate, the one blessed with natural affability and charm. Even Al Gore worried about the Texas friendliness of his opponent, warning in his convention speech that the election is ''not a popularity contest.''
Since the end of the conventions, however, as Gore has pulled even or ahead in national polls, Bush has appeared to soften his claim to the popularity prize, through a series of carefully planned negative tactics and accidental missteps. Although some Republicans believe Bush needs to become more hard-nosed to win, it is unclear whether he can do so and still capitalize on his personality, arguably his greatest asset.
In the last three weeks, Bush has all but called Gore a liar on the stump, then approved two personal attack ads to air in a rotation of 21 states. Last week, he accidentally called a reporter a vulgar name before an open microphone, then refused to apologize.
Yesterday, Bush came under fire for what appeared to be another negative move: an ad that ostensibly criticized Gore's prescription drug plan, but subliminally flashed the word ''rats'' on the screen. Bush insisted that, too, was a mistake, caused by a computer editing glitch, but he refused to condemn the designer who made it, and implied that, while the tactic was reprehensible, there was nothing really wrong with his own ad.
''One frame out of 900 hardly in my judgment makes a conspiracy,'' Bush said. ''I am convinced this is not intentional. We don't need to play, you know, cute politics.''
Bush said he would not pull the ad, which has been running for more than two weeks, because it was due to end its rotation anyway. Asked whether Alex Castellanos, the designer of the ad, should continue to produce spots for the campaign, Bush said: ''Yeah, as far as I'm concerned.''
News of the `Rats' message first broke on the Fox News Channel weeks ago, but only yesterday, when it was printed on the front page of the New York Times, did it become an issue for Bush. Although he reviewed an e-mailed version of the ad and approved it, the Texas governor said he was unaware of the presence of the word ''rats'' until yesterday.
The Federal Communications Commission developed a policy in 1974 recommending against using subliminal advertising. It has not investigated the Bush ad because it has not received any complaints, officials said.
Like Bush, several Republicans brushed the contretemps over the ad aside as a trivial distraction. But others were more critical, regretting that Bush had failed to convey his message of the day, catastrophic health care.
''This was silly, and you can't make silly mistakes in a presidential campaign in September. Somebody ought to have the grace to resign,'' said Scott Reed, a Republican strategist who was Bob Dole's campaign manager in 1996. ''One of Bush's strongest assets is his upbeat, optimistic message. This silly business undercuts that.''
Bush has been struggling to find ''momentum'' - an intangible force that suggests a combination of good poll numbers, positive media coverage and successful campaign events - for at least the last week and a half. After stumbling over his tax plan in late August, Bush kicked off the post-Labor Day campaign with an incident that overshadowed his policies for days: The insult of Adam Clymer, a New York Times reporter, in front of an open microphone.
That incident, which was clearly accidental, came on the heels of two negative ads about Gore that Bush approved. The first, which shows a clip of Gore at a Buddhist temple fund-raiser and mocks his claim to have invented the Internet, was described by Bush as ''tongue-in-cheek.'' The second, which barely saw the air but was promoted heavily by the campaign, ridiculed Gore for agreeing to debate ''anytime, anywhere,'' then declining a last-minute invitation to appear on NBC's ''Meet the Press.''
But the ads received harsh criticism from Republicans, and they have not had any noticeable impact in the polls, which continue to show the two candidates in a dead heat. At the same time, a Time/CNN poll released this week showed more voters believed Bush was running a negative campaign than Gore.
''It has not been a good two-week period for them,'' said Darrell West, a political science professor at Brown University. ''I think people are taking another look at Bush, because you have this example of outrageous advertising, you have the Adam Clymer comment, and you have the Bush people pulling one of their attack ads.''
He continued: ''Over the last two weeks, there have been so many distractions that Bush has been very ineffective at getting his message out.''
